/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.nifi.controller;

import org.apache.nifi.annotation.behavior.InputRequirement.Requirement;
import org.apache.nifi.components.validation.ValidationStatus;
import org.apache.nifi.components.validation.ValidationTrigger;
import org.apache.nifi.connectable.Connectable;
import org.apache.nifi.controller.scheduling.LifecycleState;
import org.apache.nifi.controller.scheduling.SchedulingAgent;
import org.apache.nifi.controller.service.ControllerServiceNode;
import org.apache.nifi.controller.service.ControllerServiceProvider;
import org.apache.nifi.logging.LogLevel;
import org.apache.nifi.nar.ExtensionManager;
import org.apache.nifi.processor.ProcessContext;
import org.apache.nifi.processor.Processor;
import org.apache.nifi.processor.Relationship;
import org.apache.nifi.registry.ComponentVariableRegistry;
import org.apache.nifi.scheduling.ExecutionNode;
import org.apache.nifi.scheduling.SchedulingStrategy;

import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicReference;
import java.util.function.Supplier;

public abstract class ProcessorNode extends AbstractComponentNode implements Connectable {

    protected final AtomicReference<ScheduledState> scheduledState;

    public ProcessorNode(final String id,
                         final ValidationContextFactory validationContextFactory, final ControllerServiceProvider serviceProvider,
                         final String componentType, final String componentCanonicalClass, final ComponentVariableRegistry variableRegistry,
                         final ReloadComponent reloadComponent, final ExtensionManager extensionManager, final ValidationTrigger validationTrigger,
                         final boolean isExtensionMissing) {
        super(id, validationContextFactory, serviceProvider, componentType, componentCanonicalClass, variableRegistry, reloadComponent,
                extensionManager, validationTrigger, isExtensionMissing);
        this.scheduledState = new AtomicReference<>(ScheduledState.STOPPED);
    }

    @Override
    public abstract boolean isIsolated();

    @Override
    public abstract boolean isTriggerWhenAnyDestinationAvailable();

    @Override
    public abstract boolean isSideEffectFree();

    public abstract boolean isTriggeredSerially();

    public abstract boolean isEventDrivenSupported();

    public abstract boolean isExecutionNodeRestricted();

    public abstract Requirement getInputRequirement();

    public abstract List<ActiveThreadInfo> getActiveThreads(ThreadDetails threadDetails);

    /**
     * Returns the number of threads that are still 'active' in this Processor but have been terminated
     * via {@link #terminate()}. To understand more about these threads, such as their stack traces and
     * how long they have been active, one can use {@link #getActiveThreads(ThreadDetails)} and then filter the results
     * to include only those {@link ActiveThreadInfo} objects for which the thread is terminated. For example:
     * {@code getActiveThreads().stream().filter(ActiveThreadInfo::isTerminated).collect(Collectors.toList());}
     *
     * @return the number of threads that are still 'active' in this Processor but have been terminated.
     */
    public abstract int getTerminatedThreadCount();

    public abstract void setBulletinLevel(LogLevel bulletinLevel);

    public abstract LogLevel getBulletinLevel();

    public abstract Processor getProcessor();

    public abstract void setProcessor(LoggableComponent<Processor> processor);

    @Override
    public abstract void yield(long period, TimeUnit timeUnit);

    public abstract void setAutoTerminatedRelationships(Set<Relationship> relationships);

    public abstract Set<Relationship> getAutoTerminatedRelationships();

    public abstract void setSchedulingStrategy(SchedulingStrategy schedulingStrategy);

    @Override
    public abstract SchedulingStrategy getSchedulingStrategy();

    public abstract void setExecutionNode(ExecutionNode executionNode);

    public abstract ExecutionNode getExecutionNode();

    public abstract void setRunDuration(long duration, TimeUnit timeUnit);

    @Override
    public abstract long getRunDuration(TimeUnit timeUnit);

    public abstract Map<String, String> getStyle();

    public abstract void setStyle(Map<String, String> style);

    /**
     * @return the number of threads (concurrent tasks) currently being used by
     *         this Processor
     */
    public abstract int getActiveThreadCount();

    /**
     * Verifies that this Processor can be started if the provided set of
     * services are enabled. This is introduced because we need to verify that
     * all components can be started before starting any of them. In order to do
     * that, we need to know that this component can be started if the given
     * services are enabled, as we will then enable the given services before
     * starting this component.
     *
     * @param ignoredReferences to ignore
     */
    public abstract void verifyCanStart(Set<ControllerServiceNode> ignoredReferences);

    public abstract void verifyCanTerminate();

    /**
     *
     */
    @Override
    public ScheduledState getScheduledState() {
        ScheduledState sc = this.scheduledState.get();
        if (sc == ScheduledState.STARTING) {
            final ValidationStatus validationStatus = getValidationStatus();

            if (validationStatus == ValidationStatus.INVALID) {
                return ScheduledState.STOPPED;
            } else {
                return ScheduledState.RUNNING;
            }
        } else if (sc == ScheduledState.STOPPING) {
            return ScheduledState.STOPPED;
        }
        return sc;
    }

    /**
     * Returns the physical state of this processor which includes transition
     * states such as STOPPING and STARTING.
     *
     * @return the physical state of this processor [DISABLED, STOPPED, RUNNING,
     *         STARTIING, STOPIING]
     */
    public ScheduledState getPhysicalScheduledState() {
        return this.scheduledState.get();
    }

    /**
     * Will start the {@link Processor} represented by this
     * {@link ProcessorNode}. Starting processor typically means invoking its
     * operation that is annotated with @OnScheduled and then executing a
     * callback provided by the {@link ProcessScheduler} to which typically
     * initiates
     * {@link Processor#onTrigger(ProcessContext, org.apache.nifi.processor.ProcessSessionFactory)}
     * cycle.
     *
     * @param scheduler
     *            implementation of {@link ScheduledExecutorService} used to
     *            initiate processor <i>start</i> task
     * @param administrativeYieldMillis
     *            the amount of milliseconds to wait for administrative yield
     * @param timeoutMillis the number of milliseconds to wait after triggering the Processor's @OnScheduled methods before timing out and considering
     * the startup a failure. This will result in the thread being interrupted and trying again.
     * @param processContextFactory
     *            a factory for creating instances of {@link ProcessContext}
     * @param schedulingAgentCallback
     *            the callback provided by the {@link ProcessScheduler} to
     *            execute upon successful start of the Processor
     * @param failIfStopping If <code>false</code>, and the Processor is in the 'STOPPING' state,
     *            then the Processor will automatically restart itself as soon as its last thread finishes. If this
     *            value is <code>true</code> or if the Processor is in any state other than 'STOPPING' or 'RUNNING', then this method
     *            will throw an {@link IllegalStateException}.
     */
    public abstract void start(ScheduledExecutorService scheduler, long administrativeYieldMillis, long timeoutMillis, Supplier<ProcessContext> processContextFactory,
                               SchedulingAgentCallback schedulingAgentCallback, boolean failIfStopping);

    /**
     * Will stop the {@link Processor} represented by this {@link ProcessorNode}.
     * Stopping processor typically means invoking its operation that is
     * annotated with @OnUnschedule and then @OnStopped.
     *
     * @param processScheduler the ProcessScheduler that can be used to re-schedule the processor if need be
     * @param executor
     *            implementation of {@link ScheduledExecutorService} used to
     *            initiate processor <i>stop</i> task
     * @param processContext
     *            the instance of {@link ProcessContext}
     * @param schedulingAgent
     *            the SchedulingAgent that is responsible for managing the scheduling of the ProcessorNode
     * @param scheduleState
     *            the ScheduleState that can be used to ensure that the running state (STOPPED, RUNNING, etc.)
     *            as well as the active thread counts are kept in sync
     */
    public abstract CompletableFuture<Void> stop(ProcessScheduler processScheduler, ScheduledExecutorService executor,
        ProcessContext processContext, SchedulingAgent schedulingAgent, LifecycleState scheduleState);

    /**
     * Marks all active tasks as terminated and interrupts all active threads
     *
     * @return the number of active tasks that were terminated
     */
    public abstract int terminate();

    /**
     * Determines whether or not the task associated with the given thread is terminated
     *
     * @param thread the thread
     * @return <code>true</code> if there is a task associated with the given thread and that task was terminated, <code>false</code> if
     *         the given thread is not an active thread, or if the active thread has not been terminated
     */
    public abstract boolean isTerminated(Thread thread);

    /**
     * Will set the state of the processor to STOPPED which essentially implies
     * that this processor can be started. This is idempotent operation and will
     * result in the WARN message if processor can not be enabled.
     */
    public abstract void enable();

    /**
     * Will set the state of the processor to DISABLED which essentially implies
     * that this processor can NOT be started. This is idempotent operation and
     * will result in the WARN message if processor can not be enabled.
     */
    public abstract void disable();

    /**
     * Returns the Scheduled State that is desired for this Processor. This may vary from the current state if the Processor is not
     * currently valid, is in the process of stopping but should then transition to Running, etc.
     *
     * @return the desired state for this Processor
     */
    public abstract ScheduledState getDesiredState();
}
